Enclosed belt conveyor

ABSTRACT

A belt conveyor is disclosed in which the belt is equipped with upwardly projecting material-engaging fingers and wherein at least that section of the working run which passes between feed and discharge is enclosed by a close-fitting conduit. A belt construction is also disclosed whereby at least part of the material-engaging fingers are constructed from or tipped with a low-friction abrasion-resistant material to provide bearing elements. In some cases, only part of the material-engaging bearing fingers serve as bearing elements. In such instances, the bearing element fingers extend outwardly to a greater distance than the other fingers and serve as spacers holding the nonbearing fingers away from the conduit. The underside of the belt may also be provided with relatively thin abrasion-resistant bearing elements.

United States Patent [72] Inventors Leon A. Chamberlain; 2,281,0264/1942 Sinden 198/168 Clarence R. Campbell; Leif T. Stokes, all of3,306,218 2/1967 Reeves 198/129 21 A l N Utah Primary Examiner--EdwardAv Sroka fi g 21 I969 Attorneys-Robert R. Finch and Richard F Bojanowski[45] Patented Sept. 7, 1971 [73] Asslgnee gz fitz g gg ABSTRACT: A beltconveyor is disclosed in which the belt is equipped with upwardlyprojecting material-engaging fingers and wherein at least that sectionof the working run which [54] ENCLOSED BELT CONVEYOR passes between feedand discharge is enclosed by a closefitting conduit. A belt constructionis also disclosed whereb l 1 Claims, 7 Drawing Figs. y at least part ofthe material-engaging fingers are constructed [52] US. Cl 198/ 198 fromor tipped with a f i ti abrasionqesistant material [51] P' B65g15/42 toprovide bearing elements. In some cases, only part of the [50] Field ofSearch 198/198, materiahengaging bearing fingers serve as bearingelements 129127 163 In such instances, the bearing element fingersextend out- I 56] References Cited wardly to a greater distance than theother fingers and serve as spacers holding the nonbearing fingers: awayfrom the conduit. UNITED STATES PATENTS The underside of the belt mayalso be provided with relatively 2,163,353 6/1939 Roth 198/168 thinabrasion-resistant bearing elements.

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SHEU 1 [1F 2 INVENTORS CLARENCE R. CAMPBELL LEON A CHAMBERLAIN a LEIF TSTOK s,

ATTORNEYS INVENTORS. CLARENCE R. QAMPBELL LEON A CHASA4%E%LS.AIN

LEI K BY fi 7 g ATTORNEYS ENCLOSED BELT CONVEYOR BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates generally tobelt conveyors and in particular to a belt conveyor of the type having aworking and return run, with the working run passing through aclosefitting conduit and wherein the working surface of the belt isequipped with material-engaging members.

2. Description of the Prior Art Conveyors employing belts runninginclosed tubes or conduits and equipped with material-engaging memberssuch as fingers for conveying flowable materials have recently come intouse and are finding broad acceptance in many areas for moving andelevating materials.

In conveyors of this type, it is possible to subject the belt to areverse bend and to angle it upwardly from the horizontal to dischargeat a higher elevation, making it especially useful in conveying flowabletype materials.

In such constructions, as the belt turns upwardly in a reverse bend, thefingers bear against idler pulleys at the point of turning or bending,thus causing bending and weakening of the fingers. This form ofconstruction has the further disadvantage of higher initial cost becauseof the pulleys and the need to enclose them in the conduit through whichthe materials are conveyed. Moreover, maintenance expense is high due tothe extra care required to keep the areas containing the pulleys freefrom materials that may spill off the belt.

OBJECTS OF THE INVENTION It is a primary object of this inventiontoprovide a belt conveyor of the type described in which reverse turns aremade with a minimum number of pulleys, thus avoiding the installationand maintenance costs resulting therefrom.

Another object is to provide a conveyor'system in which guidance of thebelt through the curved or bent conduit is effected by hearing meansprojecting outwardly from the belts surface, which also serves asmaterial-engaging projections for conveying.

Still another object is to provide a conveyor belt having nonbearingmaterial-engaging fingers projecting from its working surface incombination with a plurality of spacedapart bearing means extendingoutward from the same belt surface beyond the fingers to slidablycontact the inner walls of a conduit enclosing the belts working run andthereby prevent contact of the nonbearing material-engaging fingers withthe walls of the conduit.

Another object is to provide a conveyor system wherein the lateralmovement of the conveyor belt is limited.

Other objects of this invention will be more readily apparent from thedisclosure and drawings which follow.

SUMMARY OF THE INVENTION These and other objects of this invention areattained by a conveyor which comprises generally an enclosed conveyorbelt having a plurality of spaced-apart, low-friction slide membersextending outwardly from at least the upper surface of the belt forslidable contact with a walled conduit through which the belt moves.

The low-friction slide members are arranged on the belt so that theentire surface from which they extend is spaced from the conduit walls.This minimizes belt drag and avoids serious frictional wear of the beltssurface as the belt passes through the conduit and particularly as thebelt is negotiating bends or turns within the conduit.

There is also illustrated a further modification which includes means inthe belt enclosure for tracking or guiding the belt in a fixedlongitudinal path to thus prevent the sides of the belt from abradingagainst the conduit sidewalls.

BRIEF DESCRIPTION OF Til-IE DRAWINGS FIG. 1 is a side view of a conveyorembodying the invention, certain portions being cut away and internalparts shown in dotted lines for purposes of clarity.

FIG. 2 is a sectional view taken in the plane of line 2-2 of FIG. 1.

FIG. 3 is a sectional view similar to FIG. 2 but illustrating a modifiedembodiment of this invention.

FIG. 4 is an enlarged sectional view of the material-engaging membersshown in FIG. 3.

FIG. 5 is a sectional view similar to FIG. 2, but illustrating adifferent embodiment of the invention.

FIGS. 6 and 7 are sectional views similar to FIG. 2, illustrating stillother variations or embodiments of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings,numeral 10 designates generally the conveyor apparatus of thisinvention.

As shown, a continuous or endless flexible belt 12 has lowfriction slidemembers 14 extending upwards from its outer or working surface 16 andother low-friction slide members 18 extending downward from its undersurface 19. The belt is trained about a drive pulley 20, a first idlerpulley 22 and a second idler pulley 23. The belt pass-es through aclosed conduit or tube 24 which provides enclosures 26 and 28 for boththe working run and return run of the belt respectively. As will bedescribed more fully hereinafter, the idler and drive pulleys are bothlocated adjacent the same end of the conveyor. The conduit has an outerwall 30, and inner wall 32, and side walls 34. The conduit, incombination with the low-friction slide members 14 and 18, enables thebelt to negotiate turns within the conduit with a minimum of frictionalresistance and belt strain. A feed inlet 36 and feed outlet 38 arelocated at opposite ends of the conduit enclosing the working run.

In other words, except for pulleys associated with driving of the beltor in negotiating turns of or greater, the conduit which encloses theworking run of the belt (between inlet and outlet) is unbroken; that is,it is not interrupted by pulleys. Guidance of the belt is achieved bythe walls of the conduit and the low-friction slide members extendingfrom the belts surface.

The elimination of internal intermediate rollers along the workingsurface of the belt eliminates the need for special high-cost bearingconstructions and avoids the special maintenance costs incident thereto.7

As best shown in FIG. 2, the bearing elements 14 extending upwardly fromthe belt are fingerlike and engage the material being conveyed tothereby assist in moving the material through the conduit.

In accordance with this invention, the fingers 14 may be constructedfrom materials different from that of the belt and are, in fact,expressly selected to provide the belt with easy sliding against theconduit walls.

Thus, while the belt may be made from a reenforced rubberlike materialhaving a relatively high coefficient of friction, the bearing elementsare constructed from a hard, durable plastic type material having asubstantially lower coefficient of friction.

Although the members extending below the belts surface have a size andshape different from that of the upper members, they are constructedfrom the same types of low-coefficient of friction material and serve inessentially the same capacity as do the upper members; that is, theyspace the belt from the conduit and slidably contact the conduit walls,thus reducing friction and lowering operating power requirements whileincreasing belt life.

Illustratively, when the working run of the belt passes through theconduit in contact with its bottom wall or when the belt makes adownward turn, the lower bearing members support the belt in slidingcontact with the conduit walls. When the belt makes an upward or reverseturn or when the return run passes through the conduit, the upper slidemembers contact the conduit walls to keep the belt spaced therefrom.

As shown in FIG. 2, the upper and lower bearing members are held firmlyin position on the belt by connecting stems 42 which pass throughopenings in the belt.

In the modification illustrated in FIGS. 3 and 4, an already existingmolded nubbed belt 46 has been modified by adding tips 48 and basemembers 50 made from a suitable low-friction bearing material. The tipsand base members may be permanently attached to the nubs by neck membersor stems 52 and 53 respectively or may be detachable for easyreplacement when they become worn. In this modification, only part ofthe fingers are tipped, but their resulting increased length spaces theunti'pped fingers away from the upper conduit wall.

In FIG. 5, a still further modification. is shown wherein the nubbedbelt is provided with sideflanges 60 to retain extremely fine orflowable materials on the working surface of the belt. The replaceabletips 48' and base members 50 shown. in FIG. 4 have been replaced withtransverse ribs 66 and 68' having a height and width sufficient to spacethe belt surfaces and/or fingers from the conduit walls. By extendingthe ribs beyond both edges of the belt, the outer ends of the ribs actas bearings against the conduits sidewalls.

In still another embodiment of this invention, as shown: in FIG. 6,guidance of the conveyor belt is achieved by substantially parallelspaced-apart longitudinal guide strips 70 and 72 along the upper surfaceof the inner. wall 32 of the conduit 26. A flanged nubbed belt 74 havinglow-friction slide members and 18 connected bystems 33 extending fromits upper and lower surfaces respectively is trained through the conduitwith the outer rows of the lower slide members adjacent the guide stripsso that their lateral movement is restricted thereby. This limitslateral belt movement and maintains the belt edges spaced from theconduit sidewalls 34..

In the embodiment illustrated in FIG. 7, a plurality of relativelyshallow guide channels 76' are formed on the inner wall 32, one for eachrow of lower slide members" 18; Such channels may be conveniently formedby aligning; a plurality of parallel longitudinal strips 70 along thesurface of inner wall 32. The depth of the channels is lessthan thethickness of the slide members so that the latter may still hold thebelt away from the wall 32 while still providing the limited bearingsurface for the belt.

While the invention has been described with reference to severalspecific embodiments, it should be understood that certain changes inconstruction may be made by one skilled in the art and would not therebydepart from the spirit and scope of this invention, which is limitedonly by the claims appended hereto.

What is claimed is:

l. A conveyor belt comprising a flexible belt having a working surface,a plurality of spaced-apart material-engaging projections extendingupward from said working surface and a plurality for low-frictionbearing elements extending above the tops of the material-engagingprojections, said low-friction bearing elements having a coefficient offriction substantially lower than that of said material-engagingprojections.

2. A belt conveyor comprising an endless belt trained aboutspaced-apartpulleys and having a working run and a return run, a curvedconduit enclosing the working run of the belt, spaced-apartmaterial-engaging projections extending upward from the upper surface ofsaid belt and a plurality of low-friction bearing elementsextendingiabove' the tops of the-material-engaging projections formaintaining the material-engaging projections in spaced relationship tothe wallsof said conduit, said low-friction bearing elements having acoefficient of friction substantially lower than that. of saidmaterial-engaging projections.

3. Apparatus according to claim. 2 with the addition of plurality ofspaced-apart, low-friction bearing elements on the lower surface of saidbelt to maintain said surface in spaced relationship to the wallsof theconduit.

4. Apparatus according to claim 3 wherein the bearing elementsaresecured to the top and: bottom surfaces of said belt by stems passingthrough said belt.

5. Apparatus according to claim 4' wherein the bearing elementsextending from at least one ofsaid top and bottom surfaces of said beltcomprise ribs extendingtransversely of said belt.

6. Apparatus for conveying: materials at various angles of inclination,comprising amol'ded, endless flexible belt, trained about spaced-apartpulleys-and having material-engaging projections extending from theupper surface thereof, walled conduits separately enclosing the workingand return runs of said belts, means for moving said belt through saidconduit, and a plurality of spaced-apart, low-friction bearing memberson said upper surface extending above" said material-engagingprojections and adapted to slidably contact the wall of said conduit toprovide a bearing thereagaihst while maintaining said material-engagingprojections in spaced relationship thereto.

7'. Apparatus according toclai'm 6 wherein said belt. is provided with aplurality of spaced-apart,low-friction bearing-elements projecting fromthe belts under surface for slidably contacting the wall of saidconduitwhile maintaining said surface in spaced relationship tosaidtwall.

8. Apparatus according to claim 7' wherein the bearing members aredetachably secured. to the belt by intermediate stems passing throughsaid belt.

9. Apparatus according to claim 6 wherein the low-friction bearing.members are tipped extensions detachably mounted to the top of theplurality of material-engaging projections.

10. Apparatus according toclaim 7, with the addition of longitudinalguide means on an inner' surface of said conduit forming at least onerelatively shallow channel for receiving at least part of saidlow-friction bearing elements projecting from the belt'sundersurface.

11. The conveyor belt of claim 1, including low-friction bearingelements extending below the bottom surface, of said belt.

1. A conveyor belt comprising a flexible belt having a working surface,a plurality of spaced-apart material-engaging projections extendingupward from said working surface and a plurality for low-frictionbearing elements extending above the tops of the material-engagingprojections, said low-friction bearing elements having a coefficient offriction substantially lower than that of said material-engagingprojections.
 2. A belt conveyor comprising an endless belt trained aboutspaced-apart pulleys and having a working run and a return run, a curvedconduit enclosing the working run of the belt, spaced-apartmaterial-engaging projections extending upward from the upper surface ofsaid belt and a plurality of low-friction bearing elements extendingabove the tops of the material-engaging projections for maintaining thematerial-engaging projections in spaced relationship to the walls ofsaid conduit, said low-friction bearing elements having a coefficient offriction substantially lower than that of said material-engagingprojections.
 3. Apparatus according to claim 2 with the addition ofplurality of spaced-apart, low-friction bearing elements on the lowersurface of said belt to maintain said surface in spaced relationship tothe walls of the conduit.
 4. Apparatus according to claim 3 wherein thebearing elements are secured to the top and bottom surfaces of said beltby stems passing through said belt.
 5. Apparatus according to claim 4wherein the bearing elements extending from at least one of said top andbottom surfaces of said belt comprise ribs extending transversely ofsaid belt.
 6. Apparatus for conveying materials at various angles ofinclination, comprising a molded, endless flexible belt, trained aboutspaced-apart pulleys and having material-engaging projections extendingfrom the upper surface thereof, walled conduits separately enclosing theworking and return runs of said belts, means for moving said beltthrough said conduit, and a plurality of spaced-apart, low-frictionbearing members on said upper surface extending above saidmaterial-engaging projections and adapted to slidably contact the wallof said conduit to provide a bearing thereagainst while maintaining saidmaterial-engaging projections in spaced relationship thereto. 7.Apparatus according to claim 6 wherein said belt is provided with aplurality of spaced-apart, low-friction bearing elements projecting fromthe belt''s under surface for slidably contacting the wall of saidconduit while maintaining said surface in spaced relationship to saidwall.
 8. Apparatus according to claim 7 wherein the bearing members aredetachably secured to the belt by intermediate stems passing throughsaid belt.
 9. Apparatus according to claim 6 wherein the low-frictionbearing members are tipped extensions detachably mounted to the top ofthe plurality of material-engaging projections.
 10. Apparatus accordingto claim 7, with the addition of longitudinal guide means on an innersurface of said conduit forming at least one relatively shallow channelfor receiving at least part of said low-friction bearing elementsprojecting from the belt''s undersurface.
 11. The conveyor belt of claim1, including low-friction bearing elements extending below the bottomsurface of said belt.